How did Britain get drawn into the Second World War?

Following the invasion of Poland, as with World War I some international alliances were activated. As a result Britain and France declared war on Germany.
When the Germans attacked Poland, the Russians also attacked the country and it was divided.The Germans went on to invade Denmark, Norway, Belgium, The Netherlands and France in quick succession. They crushed any resistance with overwhelming armoured forces.

What was the Battle of Britain?

After his triumph in Europe, Hitler planned to invade Britain. First, he had to destroy the Royal Air Force to prevent it from bombing his invasion ships.

The German Luftwaffe, which was considered to be far superior to the RAF, set out to bomb the British airfields and shoot down their aircraft.The Battle of Britain began in July 1940 and continued for nearly four months. The Luftwaffe finally abandoned its attempts to defeat the RAF and the Germans realized that they had not been successful.

The German aircraft had been flying too far from home and ran short of fuel, while the RAF fighters destroyed large numbers of the invading bombers. As a result, the invasion of Britain was abandoned and Hitler soon turned his attention to invading Russia.